For various benefits, a fuel system of a motor vehicle may be configured to store a plurality of different fuels, either severally or as a mixture. In one example, a fuel system so configured may be installed in a motor vehicle whose engine is configured to consume either fuel A or fuel B, or a mixture of fuels A and B. In this example, the engine may adapt automatically to the fuel that is provided, or it may require some adjustment based on the fuel.
In another example, a vehicle may be assembled at least partly from component modules, some of which may be adaptable to different motor vehicles. For instance, two motor vehicles—one of them configured to consume fuel A and the other configured to consume fuel B—may each include a fuel system of substantially the same configuration. This approach may be taken in order to simplify motor-vehicle manufacture.
In the examples noted above, it may be beneficial for the fuel system to detect refueling and to further detect the type of fuel supplied during the refueling. Accordingly, U.S. Pat. No. 5,542,394 provides a refueling detection system and method for a motor-vehicle. This approach combines pressure-based refuel detection with a fuel-property (e.g., volatility) determination. The fuel-property determination relies on changing a fuel-injection amount provided to the engine of the motor vehicle and detecting a response of one or more engine parameters (e.g., combustion pressure). However, the inventors herein have identified various inadequacies of this approach.
For example, the indicated method of determining the fuel property may be acceptable only if it has been established that the fuel in the fuel tank is suitable for consumption by the engine under existing conditions of the engine. In some scenarios, however, the fuel in the fuel tank may be unsuitable for the engine under any circumstance, or, the engine may require some adjustment or adaptation from its current operating state in order to safely use the fuel. If, for any reason, the fuel in the fuel tank is not suitable for the engine, the indicated method of determining the fuel property may give unreliable results, or may cause degradation of engine components.
Therefore, in one embodiment, a method for registering a content change in a fuel system of a motor vehicle is provided. In this embodiment, the fuel system is configured to receive a first fuel and a second fuel into a common space. A first condition is correlated to receiving the first fuel, and a second condition is correlated to receiving the second fuel. The method comprises admitting fuel to the fuel system and indicating that the first fuel has been admitted if a condition responsive to admitting the fuel matches the first condition and does not match the second condition.
In another embodiment, a method is described for registering a content change in a fuel system of a motor vehicle, the method comprising: admitting fuel to the fuel system, the fuel system configured to receive hydrogen and compressed natural gas into a common space; indicating that compressed natural gas has been admitted if a temperature in the common space increases by more than a threshold amount when the fuel is admitted, said indicating occurring, if at all, before the compressed natural gas is consumed by an engine of the motor vehicle; indicating that hydrogen has been admitted if the temperature in the common spaces increases by less than the threshold amount when the fuel is admitted, said indicating occurring, if at all before the hydrogen is consumed by the engine of the motor vehicle; and adjusting a start-up operating parameter of the motor vehicle in response to which of said fuels is indicated to have been admitted.
Other embodiments provide more particular methods for registering a content change in the fuel system and for adjusting one or more start-up operating parameters of the motor vehicle based on the content of the fuel system.
In the methods described herein, various start-up operating parameters may be adjusted, such as fuel injection amount, injection timing, spark timing, etc. In this manner, an electronic control system of the motor vehicle may determine which fuel or fuels are present in the fuel system before providing any fuel to the engine, thereby enabling a reliable adjustment of the start-up operating parameter and avoiding the delivery of an inappropriate fuel to the engine. Further, the electronic control system may accommodate, yet distinguish between, two gaseous fuels and provide compensation for engine starting, including compensation for even the first combustion event (e.g., from engine rest) of the start.
It will be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description, which follows. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined by the claims that follow the detailed description. Further, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.